1. Field of the Invention
The present invention relates to a process for preparing a silicon carbide (SiC) device capable of operating at high temperatures.
2. Description of the Prior Art
SiC is a semiconductor capable of operation at high temperatures. The technique of growing SiC on a silicon (Si) substrate has recently been rapidly developed. It includes, for example, a chemical vapor deposition growth method according to which SiC of 5 to 10 .mu.m can be grown from SiH.sub.4 and C.sub.3 H.sub.8 on an Si substrate having a surface with Miller indice of (100). However, a large strain is built up in the grown SiC film due to differences in thermal expansion coefficient and lattice constant between the Si substrate and SiC. This leads to cracking of the SiC film in the subsequent procedure of preparing a device. Thus, in this case, the preparation of such a device is difficult. Further, evaluation of electrical characteristics of SiC involves such an inconvenience that a thin SiC film obtained by dissolving the Si substrate must be used.
On the other hand, where an SiO.sub.2 film obtained by oxidizing the surface of SiC is utilized as an insulating layer, it is known that difficulty is encountered in obtaining a sufficiently thick SiO.sub.2 film due to the oxidation rate of SiC which is by far slower as compared with Si. Accordingly, it has been anticipated that a difficulty might be encountered in preparing devices such as a MOS transistor, for example, because of difficulties in attaining insulation of wirings.